No artist since Whistler has left us as many memorable apophthegms as Andy Warhol. It’s not just that overworked line about everybody eventually being famous for 15 minutes. It’s also such astute remarks as, “An artist is someone who produces things that people don’t need to have but that he – for some reason – thinks it would be a good idea to give them.” In spite of the astuteness manifested here, Warhol struck many as being even dumber than he looked. “I never read. I just look at pictures,” is another of the utterances, which seems to prove the point. But don’t be taken in by the seemingly mindless wanderings, the refusal to make judgments, express an opinion or bother much about what he got up to. All that apparent dullness disguised a native cunning. And some would go so far as to claim that, far from not caring about the many and various subjects of his art, Warhol was as deeply involved in them as any expressionist.

That, at least, is one of the arguments advanced by the impressive exhibition at the National Gallery of Scotland, Andy Warhol: A Celebration of Life... and Death. The title already hints at the thesis: Warhol was for years preoccupied by death, and therefore engaged on an emotional level with pictures of electric chairs, plane and car crashes, famous suicide victims such as Marilyn Monroe or tragic widows like Jacqueline Kennedy. He began to paint Elizabeth Taylor, he said, only after word went round that she was terminally ill. Warhol’s preoccupation with death began, it is said, in 1962, when the curator Henry Geldzahler complained that his work, represented by soup cans and Coke bottles, was too positive. “Maybe everything isn’t always so fabulous in America,” Geldzahler said. “It’s time for some death.”

Before we examine this supposed infatuation with mortality, let us say something about the show. It is not a retrospective. Whole areas of the artist’s vast output are left untouched. There are none of those famous portraits of Mao, for instance. But it’s not that kind of show. There is, among other unusual features, a Warhol Time Capsule: all the photographs, pamphlets, postcards, newspapers and other ephemera collected by the incorrigible hoarder during a single month, then put for posterity in a box. It’s fascinating.

The show also gives us some part-reconstructions of famous installations. The first gallery here is filled with plump, floating pillows, the Silver Clouds Warhol introduced to the public at New York’s Leo Castelli Gallery in 1966. Another gallery’s walls are covered from floor to ceiling with cow wallpaper, shown at Castelli’s two years earlier. Then there are the paintings of toys on a background of fish wallpaper, more or less as they were at a Zurich gallery in 1983. There is also a room of celebrity portraits and, on another sort of wallpaper, a group of painted skulls, the colours and tones almost as nuanced as Monet’s Haystacks.

Surely the catalogue goes too far in discerning the image of a child in the shadows cast by these skulls. And the disaster pictures look as bland as everything else by Warhol. Why not take him at his word? “There was no profound reason for doing a death series,” he said. “There was no reason for doing it at all.” The same lack of discrimination was surely behind everything he did. He started out in the 1950s as a shrewd and prolific illustrator, in whose blotty, chirpy drawings of boys and butterflies (well represented here) the style was more important than the subject. He ended up an impresario, of whose entire production precisely the same might be said.

Given the sustained superiority of style over content, should Warhol be taken seriously? Wasn’t his work from the beginning as lightweight and inconsequential as he was? Wasn’t he also obsessed by celebrity far more than by real worth? He certainly admired – and pursued – Truman Capote, not because of the writer’s talent but his ability to secure invitations to all the socially exclusive parties. This is one reason why Warhol published his own magazine, Andy Warhol’s Interview. It got him the desired invitations –“I’ll go to the opening of anything,” he said, “even a toilet seat” – and the chance to get on first-name terms with the rich and famous. The last thing he wanted to print was searching interviews. His magazine makes Hello! seem like The New York Review of Books. Of course, he also made portraits of the celebrities he interviewed. If he wasn’t doing portraits of superstars such as Mick Jagger and Liza Minnelli, he was working hard at becoming the most celebrated society portraitist of the age.

Warhol, like no other artist before him – with the exception of Salvador Dali – knew how vital publicity was. He also knew the potential of industrial production methods for his burgeoning bank balance. In the studio he called The Factory, assisted by hangers-on as well as the talented, he established an assembly line on which photographic images were endlessly reproduced. As one assistant recalled: “It wasn’t called The Factory for nothing. It was where the production line for screen prints happened. While one person was making a silk-screen, somebody else would be filming a screen test. Every day, something new.” (Some of those tests can be viewed here.) Of course, the reproduction wasn’t perfect. The colours were varied, the registering was sloppy, and that was the point. Sometimes, a wipe or two across the surface personalised the product.

Warhol frequently had little or nothing to do with any of the many activities in which he was involved. His several autobiographies were the work of ghostwriters. Many of his movies were directed by others. His pop group, Andy Warhol’s Velvet Underground, was actually the creation of Lou Reed. Warhol would have sympathised with Victor Mature, who so enjoyed the efforts of his many stand-ins, he once declared he wanted them to take over an entire role so he could star in a film in which he didn’t actually appear.

Appropriately, some of the silk-screens were of already mass-produced images. Tins of soup (“Campbell’s never sent me a single can,” Warhol complained), bottles of Coke and tomato ketchup and boxes of Brillo pads were all called into service. That there was some thought behind the choice of motif is suggested by another Warhol quotation: “You know that the president drinks Coke, Liz Taylor drinks Coke, and just think, you can drink Coke, too. All the Cokes are the same and all the Cokes are good.”

It is often said that we shall never know the real Warhol. If he ever existed, he has long since disappeared in a thicket of anecdotes. So, here’s yet another Warhol suggested by another quotation: “Business is the step that comes after art. I started as a commercial artist, and I want to finish as a business artist.” And here’s another. “What do you love most?” he once asked. “That’s how I started painting money.” So, as well as the spaced-out weirdo, we have the cynical money-making machine. Don’t miss the shop next to the exit here, selling reproduction Marilyns and Coke bottles. They are no more reproductions than the Warhol “originals”, of course. Only the Andy Warhol Art Authentication Board, the body qualified to say what’s genuine and what’s not, would disagree. I could be ruder about it. I could be ruder about Warhol – though not about this entertaining show – but he wouldn’t mind in the least. “Don’t worry about the publicity,” he used wisely to say, “just measure the inches.”

Andy Warhol: A Celebration of Life... and Death is at the National Gallery of Scotland, The Mound, until October 7